import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int m = in.nextInt();
        System.out.print(sum(n,m));
    }

    public static int sum(int n, int m) {
        if (n == 1 && m >= 1 || n >= 1 && m == 1) {
            return m + n;
        }
        return sum(n - 1, m) + sum(n, m - 1);
    }
}
